Spark-plug.



a z. TUCKER & L. w'. MARKWORT.

SPARK PLUG.

APPLICATION FILED APR. 16. I914.

Patented Apr. 11, 1916.

ED STATES PATENT OFFICE.

JAMES Z. TUCKER AND LO UIS W. MA RKWORT. OF ST. LOUIS. MISSOURI.

SPARK-PLUG.

' Specification of Letters Patent.

Application filetl April 16, 1914. Serial No. 832,232.

To all whom it may concern Be it known that we, JAMES Z. TUCKER and Louis MARKwoRT, citizens of the United States, residing in the city of St;

Louis and State of Missouri, have invented certain new and useful Improvements in Spark-Plugs; and we do declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to newand useful improvements in spark plugs and the primary object of the invention is to provide a plug from which maybe derived a plurality of sparks, which enable all ofthe gas sucked into the cylinders to be utilized, thus developing maximum power for the engine.

A further object of the invention resides in providing a plug, the use of which Wlll not be accompanied by the depositing of carbon on the plug, thus preventing any short circuiting in the use thereof.

Still another object 'of the invention resides in providing an improved intermediate electrode between the main electrode and ground electrode which separates the sparks so 'as'to provide substantially a double explosion in the use of this plug.

A still furtherobject resides in providing ..a plug which is simple and durable in .con-

struction, inexpensive to manufacture,'and one which Wlll be very eflicient in use.

With these and other ob ects 1n view our invention consists in the novel features of.

construction, combination and arrangement of parts as Wlll be hereinafter referred to and more particularly pointed out in the specification and claim.

In the accompanying drawing forming a part of this application :-Figure 1 is a side elevation of our device. Fig. 2 is a vertical section therethrough, and, Fig. 3 is a bottom plan view of the device.

In describing the invention we shall refer to the drawing in which similar. reference characters "designate corresponding parts throughout the several views and in 1 indicates a substantially cylindrical body formed preferably of porcelain or other similar material having non-conducting qualities, said bodybeing enlarged at a point adjacent its lower end as indicated-at a shell or the like 3, the latter being pro vided with an internal annular shoulder 4 said nut is turned home.

indicated at 10.

which receives thereagainst the enlarged portion 2 of said body, thereby limiting the movement of'the latter with respect to the shell. The body is held in position in the shell 3 by means of a bushing nut 5 the lat- -ter being threaded into engagement with an p the threaded opening of a cylinder.

It must here be stated that the enlarged portion 2 on the body has its upper face beveled downwardly and the lower peripheral edge of the nut'5 is correspondingly beveled to contact snugly therewith when The under face of the enlarged portion 2 is likewise beveled upwardly and the extreme outer portion of this last'mentioned beveled portion is flattened to provide a narrow annular shoulder 2' which rests directly on the annular shoulder 4 of theshell 3. Through the medium of this construction, the lower portion of the body continuing from the enlarged portion 2 thereof is of the's'ame diameter as the upper portion thereof and smaller than the inner diameter of the depending annular portion 7, thus providing an annular space or chamber around the lower portion of said body. The plane of the lower peripheral edge of this depending portion 7 of the shell 3 is below the plane of the lower portionof the body 1 and extending longitudin'ally through said body is a main electrode 8 the lower portion of which projects to apoint below the plane of the lower "peripheral edge of said 'portion 7. Mounted in the lower peripheral edge" of said portion 7 and projecting to the same plane as the lower end of the electrode 8 is a ground electrode 9. Also mounted in the body 1, the same being substantially molded therein, is what maybe termed an intermediate electrode 10, the latter projecting also to the same plane with the lower'ends of the electrodes8 and 9 and the lower end of said electrode 10 is designed with a T-head as The ends of this T-head terminate at pointsin close proximityto the lower" ends of the electrodes 8 and 9, thus providing spark gaps between the electrodes 8, 9 and 10.-

- The'lower end of the body 1 at the points Patented Apr. 11 1916.

venting soot and carbon from forming on the electrode and other portions of the plug. It must here also be stated that the lower projecting portion of the body 1 is spaced from the lower projecting portion 7 of the shell 3 thus providing an annular space or clearance therebetween. This clearance is also provided to prevent carbon and soot forming on the parts of the plug. Thus short clrcuiting will be eliminated, in the use of this device.

The main electrode 8 projects. a short distance above the upper end of the body 1 of the plug and is threaded the same being engaged by the usual terminal nut 12 whereby a wire may be readily connected therewith.

In the use of the device, it will be seen that two sparks will be formed through the medium of the three electrodes which sparks are formed simultaneously and if the mixture in the cylinder is a good one,,a double explosion will take place. If the mixture is a poor one. however, this double sparking mechanism will make the explosion positive and thus this plug will be effective at all times, regardles of the carbureting conditions. At the time of an explosion, the gas which enters the space orclearance between the shell and the body and which also enters the sockets. or recesses 11 in the body, will be ignited and forced out of the cylinder,

thus carrying therewith all carbon and soot. deposits. The plug is therefore cleaned of all. deposits and is in condition for perfect have provided a simple, inexpensive and eflicient means for carrying out the ob ects of the invention, and while we have particularly described the elements best adapted to perform the functions set forth, it is obvious that various changes in form, proportion and in the minor details of construction armors may be resorted to, within the scope oi the appended claim, without departing from the spirit or sacrificing any of the prlnciples of the invention. 7

Having thus described the invention, what we claim is:

A spark plug of the class described, comprising a substantially cylindrical body formed of nonconducting material and having a pair of sockets spaced at diametrically opposite points adjacent the center of the lower end thereof, the inner walls of said sockets being concaved. an annular enlarge ment formed on the body adjacent the lower end thereof, a shell receiving said body therein and having its lower peripheral edge in a plane below the plane of the lower end of said body, the lower portion of said body being spaced from the inner Wall of the shell, means for retaining said body in the shell, amain electrode projecting from the center of the upper end of the body and extending downwardly through said body obliquely and projecting through one of the recesses in the lower end thereof. the lower terminal of said electrode being in a plane below the lower end of said shell, a ground electrodemounted on the lower end of said shell, and an intermediate electrode mounted in the lower portion of said body and projecting through the other recess therein, the lower terminal of said electrode having a T-head formed thereon approximately more than half the length ofthe radius of the lower end of said body and extending diametrically across the same from a point adjacent the main electrode in one recess across the other recess to a point adjacent the ground electrode.

In testimony whereof we have hereunto set our hands inpresence of two subscribing witnesses JAMES Z. TUCKER.

LOUIS W. MARKVVORT. Witnesses:

HARRY PECANT, lloan'rra PECAN'I.

topics or this patent may be obtained for five cents each, by addressing the @oaailoaer o1? Patents, woahtngtommt.

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